1. Field
The present invention relates to a lithographic apparatus and a method for manufacturing a device.
2. Related Art
A lithographic apparatus is a machine that applies a desired pattern onto a substrate or part of a substrate. A lithographic apparatus can be used, for example, in the manufacture of flat panel displays, integrated circuits (ICs) and other devices involving fine structures. In a conventional apparatus, a patterning device, which can be referred to as a mask or a reticle, can be used to generate a circuit pattern corresponding to an individual layer of a flat panel display (or other device). This pattern can be transferred on (part of) the substrate (e.g., a glass plate), e.g., via imaging onto a layer of radiation-sensitive material (resist) provided on the substrate.
Instead of a circuit pattern, the patterning means can be used to generate other patterns, for example a color filter pattern or a matrix of dots. Instead of a mask, the patterning device can comprise a patterning array that comprises an array of individually controllable elements. The pattern can be changed more quickly and for less cost in such a system compared to a mask-based system.
A flat panel display substrate can be rectangular in shape. Lithographic apparatus designed to expose a substrate of this type can provide an exposure region that covers a full width of the rectangular substrate, or which covers a portion of the width (for example half of the width). The substrate can be scanned underneath the exposure region, while the mask or reticle is synchronously scanned through the projection beam. In this way, the pattern is transferred to the substrate. If the exposure region covers the full width of the substrate then exposure can be completed with a single scan. If the exposure region covers, for example, half of the width of the substrate, then the substrate can be moved transversely after the first scan, and a further scan is typically performed to expose the remainder of the substrate.
The device pattern and/or corresponding radiation dose pattern can be defined descriptively, for example in terms of vectors and/or groups of vectors (using hierarchy, for example). The GDSII (Graphical Design System II) format is in common use for defining flat panel displays, for example, and makes use of a vector-based description with hierarchy.
Such “high-level” descriptive representations, which typically comprise a certain degree of intrinsic compression, may need to be converted to bitmap data in order to generate a control signal suitable for a patterning array. In addition, the resulting control signal needs to be provided to the patterning array substantially in the order in which individual exposures are to be made, and at a suitable speed. This becomes difficult for complex device patterns due to the enormous size of the bitmap representations and the associated difficulties concerning storage, data conversion steps (to the bitmap data, for example) and/or transmission, for example.
Therefore, what is needed is a system and method to more effectively use pattern data.